Stoker mechanism



Jan. l5, 1952 c. w. BROS STOKER MECHANISM 5 Sheets-Shee?l l Filed Jan.24, 1949 INVENTOR. CHESTER l/\/. BROS MMQ/m n: Uwe c P u ATTORNEYS Jan.15, 1952 c. w. BROS STOKER MECHANISM Filed Jan. 24, 1949 5 Sheets-Sheet2 j ma 45 46 IfV VEN TOR. CHESTER VL/ BROS ATTORNEYS Jan. 15, 1952 Q WBROS 2,582,583

, sToKER MECHANISM Filed Jan. 24, 1949 5 Sheets-Sheet 5 INVEN TOR. f'Cf-STER W 5R05 ATTORNEYS Jan. 15, 1952 c. w. BROS 2,582,583

STOKER MECHANISM Filed Jan. 24, 1949 5 Sheets-Sheet 4 I N V EN TOR.CHESTER W BROS BUMMWW ATTORNEYS Jan. 15, 1952 c. w. BROS 2,582,583

STOKER MECHANISM Filed Jan. 24, 1949 5 Sheets-Sheet 5 D C (l Y INVENToR.CHESTER Vl/ BROS BTM/0mm ATTORNEYS Patented Jan. 15, 1952 UNITED STATESPATeNToFF1cE- sroKER MECHANISM chester W. Bros, Edina, Minn.,'assignor mWm. Bros Boiler & Manufacturing Co., Minneapolis, Minn., a corporationof Minnesota Application January 24, 1949, Serial No. 72,4437' 7 Claims.

This invention relates to stoker mechanis and more particularly tooverfeed stokers of the sprinkler type. Such stoker mechanisms are alsosometimes called spreader stokers. VThe term .sprinkler will be usedherein and will be understood to include both the sprinklerror spreadertypes, however designated. l

During the operation of overfeed sprinkler stokers the fuel is deliveredintermittently by an intermittently operated feeding mechanism, and fromthis the coal falls upon a rotating element which strikes the fallingcoal and impels or sprinkles it into the combustion space where thelighter particles are burned in suspension, the heavier particlesfalling onto a grate where combustion is completed.

Various intermittent coal feeding. mechanisms have been provided, onetype being exemplied by my prior Patent No. 2,163,825. In this patentthe fuel is delivered from a hopper or feed spout to afeed plate wherethe fuel is periodically shoved forwardly toward the furnace by. meansof a reciprocating feed shoe and a quantityv of coal, which is thusmeasured off and moved by each forward motion of the feed shoes, ispushed forward and shoved oif the deliveryend of the feed plate for eachworking stroke of the feed mechanism. As the fuel falls it is engaged bya Abladed rotor arranged below the delivery end of the feed plate, andsince the rotor is revolving at relatively high speed, the rotor bladesstrike the falling particles of fuel and impel or sprinkle them into thecombustion space where the particles are burned, partly in suspensionand partly on the grate at the bottom of the combustion Usually theiiner particles burn in suszone. pension and the heavier particles,which may ignite and partially burn before they fall onto` the grate,are then consumed on the grate below.- In some instances a chain ortraveling grate is used in a furnace of this type and always a thin fuelbed is used. This type of stoker mechanism is highly responsive to loadfluctuation as the combustion rate can be changed widely and rapidly.

Other types of mechanisms are also used for intermittently movingforward measured (metered) quantities of fuel, which is then sprinkledby the revolving rotor situated below the feed device. In another formof such mechanism the coalis moved forward periodically and in somewhatmetered amounts by a, small feed conveyor (belt or chain type) that isactuated intermittently, step-by-step, the coal being delivered 01T theend of the conveyor and onto the revolving rotor for thesprinkling-operation. i Thus, in all stokers 4of this character thereisa.

Vvamounts of coal onto the sprinkler element. The

average feed rate is varied, either by changing the frequencyA of strokeormovement ofthe feed means or bychanging theY length of thestroke ordistance of movement of feed belt or other feeding means for eachfeeding movement of the device. v v

In the operation of sprinkler stoker mechanisms of the aforesaid typethe fuel does not fall constantly upon the rotor but is delivered to therotor intermittently due to the reciprocatingmotion of the feedshoehonthe feed plate or intermittent forward motion of feed conveyor*or other feed means. yAccordingly, the yrotor delivers fuel particleslinto the furnace in a cyclic manner with practically all the coal'beingv delivered on the forward movement of the intermittent feedingmechanism and practically none during the pause or back stroke of thefeeding mechanism preparatory to obtaining Va 'fresh charge of fuel forthefnext cyclefThe'refore, in the operation of sprinkler Stokermechanisms, whetherof the feed shoe or conveyor feed'type,

'there is an appreciable period of 'time yin each feeding cycle (40% to50%) during which fuel is not being fed, and during these periods ofmini.- mum feeding there is little or no coal impelled into the furnace.This intermittent feeding of fuel into the furnaceA causesuctuation'in'the furnace draft, puflng out of ltheV furnace, difficultywith 'draft'controlapparatus and, to some degree, unfavorablevcombustion eiciency which arises out of thej following circumstance.

In the operation of all spreader stokers the coal, consisting of fineand coarse particles in a variety of sizes, isA impelled into thecombustion space. Ignition is'rapid, almost to the pointl of explosion,and fine particles are consumed before they 'can fall to the grate. Anylparticle 'which is'not completely burnedduring its fall through thecombustion space burns on the grate. As explained above, the coal feedis intermittent, being usually about 25 to 50 strokes or feeding motionsper minuteA with 'a pause (or a condil ltion of non-feeding) betweeneachfeeding' rnction. Integrated, there is a conditionof coal feedingfor roughly 50% of the time and a conbefore falling on the grate,constant feed of air for combustion has oifered the disadvantage that ifthe combustion air is sufficient in amount to effect complete combustionof the fines in suspensionY while they are being fed, the same rate offeed of air for combustion represents an excess when nov (fines)A coalis being fed. This has the net effect of increasing the average excessair passing through the furnace and* a consequent decrease in CO2content in the nue gases. There is presently available no practical wayof varyingVV combustion cyclically to compensate for thes cyclical feedof the fuel. There has likewise been no practical way, prior to thisinvention, for at taining a reasonably constantl rate of fuel in?jection into the furnace with sprinkler stokers.

It may be stated parentheticall-y'thatintermittent feed mechanisms areuniversally usedin sprinkler feed stokers because of their many adb and'reasonably''goed;operation.` 'They can vbe ay wide" range" offfeedingrates*y while-still being driven by small horsepower'alternatingoiirreht motorsof conventional-design. The design Aandconstruction of accurate" continl'l'olisefeed coal feeding'dev'cselplbl'e l0f AWide'I varitions'riilerate of feed is dinicult andcostly and such few'devices'l that' have bere'lf'l eliperimente'd Withhave not been" s''atisfact'oly"fony thestahd'pOit' of peiatn.There-fore;- ffr is known, theyfha've never been 'usedl in commercialingstallations.l

'It is lorie Of the "bl"'aidf" bjects'ff the vies'erlt inventior toprovide' ani i'r'ilpr'oved= cyclic sprinkler Stokermeclianish-whereinthe fel is' delivered to the-finnace in accurately-'controlled amountsand at-y substantially constantx rate, throlighout''thecomplete'v cycleto thel rotating distrihuting'nlfechanism'. Y e l Itis' ai 'further'object'A of the V.invent-ion toi p'rovideV an improved overfeedistokerof'thespr'inkier-type wherein granular fuel is fedinterr'nitten'tlyV andfyet" delivered at a; substantially Vconetant rate throughot' the cycleoffo'per'ation of the feedmecha'nisln to therot'or mechanism 45oftheiistokerfordstributionthereby'into the conlbustionspace.`

It is another ob'jeet' oftheinventiorr td' provide; an'l improved"sprinkler' ovevrfeed Vstoke'r inechar'iisln` wherein thefllel fedintermittently` in accurate, yetv selectivelyv variable amountshy anrostillsting mechanism oh a feed plate' ahdthe'ieedi'plateis deflectedora lpart thereofjose'illated*during a portion of theoscillatingcyel'eof the 'feed mechanishizso as to provde a nearlyv unifrmdeliveryofthe" granular fcelfrom therfeeeplate to the rotating' element o'f thesprinkler mechanism. Y y l Itk f iither" object-.of the invention Vtoprofvide an improved sprinkler Stoker nfehaflislrl hating a fuelfeeaiiiate provi-dec,withv a deniectable,` slidable', ,or otherwiselmovable tip and an oscillatory feed 'shoe Vinteroei'iheeted' therewithforl changing thejpo'sitionof th tip to cause `fuel to' lie-delivered'therefrom during those portions of the oeciliatory action,v or theY ieeeshoe when nfuel would normally be delivered by" th'e latter.

ther and further objects of theV invention i'ncludei'the provision ofspecicmechaniss lfor a'cemplihi'rl'g the aflesaidreslll-ts and alsoinclude those objects inherent in theapparatu's herein'Y illustrated;Vdescribed andi claimed:`

'I'hei invention. isY illustra-ted vwith" @reference to, thev 'drawingsiff-WhichL corresponding numerals refer to' thsameparts and inwhichFigure 1 is a side elevational View, partly in section, of oneillustrative embodiment of the invention showing the stoker mechanismand a section of the boiler or furnace wall to which the stokermechanism is applied. Figure 1 shows the intermittent feed mechanism atthe completionof a feeding stroke; A

Figure 2 corresponds to the apparatus shown in Figure" l' and is anenlarged fragmentary side sectional view of a portion of the apparatusillstrating the apparatus at an intermediate position-,during its cycleof operation;

Figure 3 corresponds to Figures 1 and 2 and is also anenlarged'fra'gmentary side sectional view showing th'apparatus at thebeginning of its y'cleof' operation;

Figure .4'i`s alfragmentary Side elevational View,

partly in section, showing another illustrative embodiment of theinvention; e Figure 5 is a fragmentary sectional view taken aliigfthe'line and inv the direction of arrows 'shovving the tip Aplateadjustment screw-of theapparatusshown inFiguree;

Figure 6 is a'fiagme-'lltary Side"elvati`onalview, partly in section,vofi a further illustrativeA form of theinvention;V

Figure 7 is a vertical* side* elevational view, partly" in section,Sliovi'fing'r another illustrative embodiment of the invention; i Figure8v is' a Yfr'a'-glider'itary side elevation'alview showing another'slightly" modified' for-m of' appara-tus.-

The illustrative embodiment of the invention shown in-Fi'g'uresV 1, 2and 3 isla stoker mechanism of the oseillating lfeed-shoe type of thesame basic character asill'ustrated in my Patent No. 2,163,825; to whihreference is made-for certain details of the mechanism. In Figures 143iemphasis is givenfto' thoserportions of the apparatus whichY aremodified as compared with the Stoker Villustrateci in Patent No'.v2,163,825 and reference is' made to that patent for manyd'etails `of thevapp'aratusthati are not illustrated in the instanti disclosure; thesedetails lbeing portant toY the* apparatus" but for simplicity yolrlittedherein.

Referringn to Figure' 1Y there is illustrated; 'a furnace'orflboilergenerally designated l having a front Wall-'generally designated 2 and aVcom bustion space e' defined' by the ignition va'rch'f and thefront'fwall 2. "The"brickvvork'forming the karchi encloses anair'ductlto Which'there areeattached'a pl'uralityfof air inletl tuyres' by meansofV which o'veiriire combustion air is de'- v livered to' the combustionspace immediately adjacent to then irl-flowing' delivery of fuel throughthe fuel aperture '8.

Upofthe front w'all ofthe boiler or furnace there is moiihtedthe mailStoker frame generally 30 designated llwhic-h is providedwith amountflange lll` 'thatis attached tothe front wall 2 of the furnace orboiler by means of bolts9.

The lowerportion ofy the frame I2 is provided with an access'. door I3`thatisheld in place by 05 as utablelatch I4. Y M

At theY` lower part=of the stoker frame l2fthere is va bladed sprinklerrotor generally designated Il whichA rotates continuouslvand at arelai-"- tively high speed fori'striking the fuel particles andimpellingthem through the. fuel inlet 8 and into 'the' combustion ,'spac'e 4; Therotcr Vis `contained `within a partial cylindrical 'space4 definedremovably attached: to" the'iflower' portion offthe Stoker -framesbyra,plurality-:of capscrewsi The space in which the bladed rotor I1 ispositioned is also partially defined by the middle portion -I of thestoker main frame. The direction of rotation of the rotorA I1 is shownby the arrow vshown adjacent its periphery. In rotating, the blades ofthe rotor engage and impel the fuel particles through opening 8 and intothe Vcombustion zone.

The details of construction of rotor I1 are described in my Patent No.2,163,825 wherein it is stated that the rotor I1 may be composed of oneor a pluralityof segments mounted upon a tubular shaft 22 which issupported in spaced relaution in respect to shaft I8 by suitable collarsnot herein illustrated. The rotor I1, tubular shaft 22 and shaft I8 allrotate as a unit, the space between the tubular member 22 and the shaftI8 serving to restrict heat communication from the rotor I1 to the shaftI8. The shaft is thus spared from operating at high temperatures. Themechanism for continuously revolving the rotor I1 in the direction shownneed not be specifically described herein since it is described indetail'in my patent referred to above. Y

Upon the front of the stokerv mechanism there -is provided a fuel hoppergenerally designated 3| that is mounted upon a bracket 32 attached tothe main frame I2 of the stoker mechanism. The bracket 32 includes anintegral bar 36 and an integral apertured guide 39 which serve jointly athreaded on the inside to receive the threaded f portions 31 of anadjustment fbolt 46. The -adjustment bolt is provided with a collar 42suitably attached to the bolt so that it rotates with the bolt. Thecollar 42 is positioned in a notch in the guide 39 and by this means thebolt 46 is permitted to rotate and yet is held-from moving endwise.Accordingly, by rotating the bolt 46 the lug 44 is moved longitudinallyof the bolt and in this manner the feed plate may be moved back andforth toward and away from the boiler or furnace wall, and hence thefuel delivery end ofv the feed plate may be adjustably positioned inrespect to the rotor so as to vary the point of delivery of fuel to therotor.

At the rear end of the bolt 46 there is provided a square sleeve 45which is positioned between the head on bolt 46 and the adjacent wall ofthe guide portion 39. The sleeve is loosely mounted upon the bolt andaccordingly, as the bolt 46 is turned, the sleeve 45 does not turn,being held from rotation byits square configuration which abuts againstthe lower surface of the feed plate 35. An indicating finger 41 isattached to the rear part of the feed plate and a plurality of indiciaare placed upon the square sleeve 45 so that the operator may know thefore and aft adjustment of the feed plate.

The feed plate 35 may be mounted horizontally, although it can also bemounted at a slight angle, as shown in my patent above referred to. Uponthe feed plate there is mounted an oscillatory feed shoe generallydesignated 48 which has a plurality of vertical walls 49 and 5I andinterconnecting top surfaces. The walls 49 and 5| are connected by theportion 52 which forms a stepdown from the top of the feed shoe. Thelower and rear portion of the hopper 3| is provided with a seal plate 13having a flexible sealing member 12 attached thereto by screws 14. vTheposition ofthe seal is adjusted so that it slides upon 8 the smoothupper surface of the feed shoe, vand therebyas the shoe is oscillated,as hereinafter described, the fuel is prevented from being pulled backas the shoev moves backwardly. The base of the front wall 49 of the shoeslides directly upon the feed plate 35. f

Oscillatory motion of the feed shoe is imparted bymeans of a pluralityof forked rocker arms 55 that are attached to an oscillating shaft 53.The rocker arms are rotated back and forth in the direction of thedouble arrow shown adjacent the shaft 53 due to the oscillatory motionof the shaft, and accordingly the upper ends 51 of the arms 55arelikewise moved back and forth in the direction of the double arrowsshown adjacent to the upper ends. The upper ends 51 of the forked arms55 are attached by links 56 to the shoe 48 and therefore as the arms 55are moved back and forth, the shoe 48 is likewise moved back and forthandr serves at each oscillatiombackwardly (away from the rotor I1) toreceive the downwardly 'moving fiow of granular fuel from the hopper 3|and on each forward movement (toward the rotor and lboiler or furnace),theffuel is shoved along the -feed plate 35, as shown in Figure 1v,toward the delivery end of the feed plate, whence it falls upon rotorI1.

The? forward end 38 of the feed plate is provided with a movable tip |65extending entirely across the front edge of the feed plate.

` In the construction, as shown in Figures 1, 2 and 3, the tip plate,which is generally designated |65, is supported by a plurality of bellcrank levers |68, these in turn being pivotally mounted on pins |69 thatare carried by brackets on the under side of the feed plate 38. The bellcrank levers |68 have downwardly extending portions I1I to which thereis pivotally attached one end of the links |12 which extend back to theoscillating arms 55 to which the links |12 are also pivotally attachedat |13. The length of the links- |12 is made adjustable so that when theforked oscillating arms 55 are in the maximum forward position, as shownin Figure 1, the bell crank levers |'68 are held in such a position thatthe tip plate |65 is in a plane approximately parallel to the feedplates 38 when the feed plate adjustment 46-41 is in its middleposition. In this position the tip plate just underlies the feed plate,as shown in Figure 1. As the oscillating 'forked arms 55 move rearwardlyand hence draw the feed shoe 48- rearwardly, to the position shown inFigure 2, the links |12 are moved rearwardly and this causes the bellcrank levers |68 toY be moved, and this causes the tip plate |65 to betilted downwardly to an intermediate position shown in Figure 2.Accordingly, approximately one-quarter of the fuel fed by the shoe onits forward stroke, which had up to that time been reposing on the end38 of the feed plate and tip plate |65, is permitted to slide-down thetip plate |65, due to the downward tipping action of the tip plate whichchanges the forward point of support of the coal. The coal willimmediately assume its natural angle of repose ofl 45`degrees and thechange in position of Vforward support of the coal will permit' aboutone-quarter of the fed amounttofsli'de onto lthe rotor.

As the motion o f the forked oscillating arms 55 isl continued to theposition shown `in Figure y3 9. as shown in Figures 4 and 5, there is athreaded portion |8| terminating in a hand wheel |81. The threadedportion 8| passes through a threaded connector |82 which has a pivotshank |83 passing through the oscillatory lever |15, the shank |83 beingheld in place on the oscillating lever arm |15 by means of a collar |84that is pinned or otherwise suitably attached so that the entireconnector |82-|03-I84 is free to pivot in the oscillating lever |15 asthe lever oscillates back and forth in moving the feed shoe. By means ofthis arrangement, which is shown in detail in Figure 5, the position ofthe sliding tip plate |16 may be adjusted with reference to the feedshoe 48. I v

. It will be noted that the point of pivotalconnection of the member |82to the oscillating lever |15 is about midway between the pivot shaft |85upon which the oscillating lever |15 is mounted. Accordingly, as thelever |15 oscillates back'and forth and moves the shoe 48 back and forthon the feed plate 35, the lever |15 through the link |80 also imparts aback-andforth sliding movement of the sliding tip plate |16, but thetotal distance (back and forth) through which the tip plate moves isapproximately one-half of the total distance moved by the feed shoe 48due to the fact that the distance from the center of the pivot shaft |85to the center of the member |82 is approximately one-half as far as fromthe pivot shaft |85 to the pin 51 by which link 56 is attached to theupper end 51 of the oscillating lever |15. Accordingly, as the feed shoe48 moves forwardly (and therefore moves a measured amount of coalforwardly), the tip plate |19 is also moving forwardly but at a rateapproximately half as fast. Therefore, the coal which is being pushedforwardly overtakes the front edge |16 of the` sliding tip plate andsome of the coal, approximately one-half thereof, is shoved off the endyof the plate and thereby falls onto the rotating spreader |1. As thefeed shoe 48 reaches its position closest to the furnace (and closest tothe rotating spreader I1) the coal that is deposited on the exposedupper surface of the tip plate |16 is left there preparatory to beingdumped as the tip plate is then drawn rearwardly during the reverse halfcycle of the oscillating movement of the mechanism. Accordingly,approximately one-half of the coal is dumped on the reverse half of thecycle and approximately one-half is dumped on the forward half 4of thecycle, thus distributing the coal relatively uniformly upon therevolving spreader rotor |1 during' the complete cycle of back and forthmovement of the feed shoe 48.

In Figure 6 there is illustrated another exemplary form of the inventionsimilar to that shown in Figures 4 and 5 but simplified in that the linkgenerally designated |90, which corresponds to the link |80 of Figures4-5, is made non-adjustable -and is fitted so that it protrudes throughopenings .|3| and |92 in the walls 5| and 49 of the feed shoe and thenextends outwardly to the left and above the feed plate 35 and isconnected to an upwardly extending lug |93 which extends upwardly fromthe upper surface of the slidable tip plate |94. The plate |94 ismounted for sliding motion back and forth in parallel guides |11 on thelower side of the feed plate 35 in the same manner as shown in Figure 4,but in this instance the lug for oscillating the sliding tip |94protrudes upwardly and to it there is pivotally attached the clevis |95on the forward end lil of'the linkzll). The rear end of the link |90 islikewise provided with a clevis |96 which is pivotally attached at |91to the oscillating lever |89.' The point of pivotal attachment |91 inFigure 6, and the point of -pivotal attachment of the member |82 ofFigure 4 may be varied up and down in any design so as to adjust therelative movement of tip plate and feed shoe and hence the amounts ofcoal delivered during each half of the cycle. The clevis |95 is'preferably made with a'knifeedge stern |98 so that it cuts through thecoal on its rear stroke and a slot is provided in the feed plate |35 at|99 so as to provide a space in which the lug |93 is free to operate.The operation of the device shown in Figure 6 is substantially identicalwith that shown in Figures 4-5.

In Figure '7 there is shown a further illustrative form of the inventionwherein the fuel is fed step-by-step in measured amounts by means of asmall conveyor from which it is delivered onto the revolving spreader orsprinkler rotor in fa manner similar to the apparatus previouslydescribed. In the device shown in Figure rI'the stoker frame 209 isprovided with a coal feed; opening defined bythe water cooled casting20|i which at its lower side 202 forms a part of the partial cylindricalchamber 203 in which the spreader rotor 204 revolves. The outer'portionA of the chamber `203 is formed by `theframe plate 205. Upon theframe 200 there is mounted 'a hopper 206 which is supportedbytheauxiliary' frame member 201. The bottom of the hopper emptiesthrough a delivery opening 208 upon a conveyor mechanism generally4designated 209 which is mounted between side wall frame platesv 2|0.The conveyor mechanism is provided with a table portion 2| upon whichthe upper portion of the conveyor belt 2|2 travels, the belt movingtoward theV furnace at its upper surface .v and .thence over the frontconveyor roller 2|3'rand thence away froml the furnace at its lowercourse of." travel until it reaches the conveyor drive roll 2|4. Theconveyor drive roll is mounted upon the shafts 2|5 which are driven by aratchet 4 wheel 2 I6. Freely pivoted upon one of the shafts y 2 l5 thereis also provided van oscillating lever 2|1 which is moved back and forthby means of 'the' link 2|8. Member 2|8 moves back and forth in thedirection of the double headed arrow 2| 9 beingV driven by a mechanismnot illustrated,

A such as the revolving crankshaft driven from( (ifi a suitable powersource. The oscillating lever 2|1 thus oscillates back and forth on theshaft 2| 5, as shown by double arrow 2 I9. The oscillating'lever 2|1 isprovided with a pawl 220 which engages the teeth of the ratchet wheel2|6 causupper end of the lever 2|1 moves laway from'thefurnace. Thus,the conveyor belt 2| 2 is caused to move step-by-step and the uppersurface thereof accordingly carries the coal C or other granular fuelforward toward the delivery end of the conveyor at roll 2|3 in astep-by-step motion, a measured amount of coal being thus propelled foreach step-by-step movement of the conveyor. If desired, the ratchetdrive mechanism comprising ratchet wheel 2|6, oscillating lever and link2|1 and 2|8 and pawl 220 can be mounted so as to drive the front roller2 |3 rather than the rear roller 2| 4. To do this it is only necessaryto connect ratchet wheel 2|6 to the tion of said plate, said tip portionbeing above said rotor, means mounting said tip portion for oscillatorytipp-ing about a substantially horizontal axis and means for moving thetip portion downwardly as the feed shoes move back to receive a freshcharge of fuel and for moving the tip portion upwardly as the feed shoemeans is moved towards said tip portion.

5. An overfeed sprinkler stoker mechanism having a substantially uprightframe, said frame being provided with a fuel delivery aperture therein,a bladed rotor mounted for rotation about a substantially horizontalaxis positioned adjacent said aperture for impelling solid fuelparticles therethrough, means for revolving said rotor, a fuel feedplate positioned substantially horizontally and having a delivery edgegenerally parallel to the axis of rotation of said bladed rotor andabove the same, a fuel delivery chute positioned above the fuel feedplate for delivering granular fuel downwardly thereon, feed shoe meansmounted on the feed plate and means for oscillating the feed shoe meansback and forth from a position where it receives the fuel to a positionwhere the fuel is pushed towards the delivery edge of the feed plate andonto the rotor, an auxiliary delivery tip for said feed plate, meansmounting said delivery tip adjacent the delivery edge of said feed platefor oscillation back and forth between a position in which it interceptsfuel delivered to the delivery edge of the feed plate and a position inwhich it spills fuel thus intercepted, and means for oscillating the tipto intercepting position as the feed shoe is moved towards said deliveryedge of the feed plate and for moving the tip to spilling position assaid feed shoe is moved away from said delivery edge.

6. An overfeed sprinkler stoker mechanism comprising an upright framewall having a central fuel delivery aperture therein, a partialcylindrical housing on said frame and a bladed fuel sprinkler rotormounted about a generally horizontal axis in said housing, said housingbeing open to the fuel delivery aperture, means for revolving saidrotor, a fuel feed plate mounted above said rotor in a generallyhorizontal position, said fuel feed plate having a delivery edge aboveand generally parallel to the axis of rotation of said rotor, a fuelchute for delivering granulated fuel downwardly on said feed plate, feedshoe means slidable back and forth on said plate, means for oscillatingsaid feed shoe means back and forth on said feed plate in a direction topush the granular fuel toward said delivery edge and then to withdrawsaid feed shoe means from the delivery edge of said feed plate,auxiliary delivery tip means adjacent and underlying the delivery edgeof the feed plate, means mounting said delivery tip means foroscillation from a position in which it forms a fuel supportingextension of the feed plate to a position in which it spills fuelsupported thereon, and means connecting said delivery tip means foroscillating said delivery tip means to spilling position as said feedshoe is moved away from said delivery tip means and for oscillating saiddelivery tip means to fuel supporting position as said feed shoe meansis moved towards said delivery tip means.

'1. A sprinkler stolzer mechanism comprising fuel supply means. a feedplate on which the fuel is delivered and along which said fuel ismovable, a rotor horizontally situated below said supply means and ofabout the width of said plate for impelling into a combustion spacegranular fuel falling downwardly off of an edge of said plate onto saidrotor, means movable along a fraction of the length of said platetowards said edge for moving towards said edge successive portions offuel during successive time intervals spaced by periods of non-deliveryand for dropping said fuel off vof said edge and along the entire Widthof said rotor, said fuel being moved from said supply means to saidrotor to be impelled thereby and means for intercepting a part of eachsuccessive portion of fuel and for delivering said intercepted partsacross the entire width of said rotor during said spaced periods ofnon-delivery, said means for moving successive portions includes a feedplate having a delivery end and a feed shoe mounted for oscillationthereon for moving the fuel in successive portions to said delivery end,said means for intercepting cornprising a tilting plate mounted adjacentthe delivery end of said feed plate.

CHESTER W. BROS.

REFERENCES CITED The following references are of record in th lle ofthis patent:

UNITED STATES PATENTS Number Name Date 2,163,825 Bros June 27, 19392,390,155 Kessler Dec. 4, 1945 2,391,597 Schwendner Dec. 25, 19452,487,464 vMosshart Nov. 8, 1949

